The purpose of this study is to evaluate effectiveness, tolerability (how well a participant can stand a particular medicine or treatment), and safety of flexible-dose of paliperidone extended release (ER) in participants with schizophrenia (psychiatric disorder with symptoms of emotional instability, detachment from reality, often with delusions and hallucinations, and withdrawal into the self), previously taking risperidone (an antipsychotic), but who are not satisfied with their treatment.